Development of a high resolution PET

A high-resolution positron emission tomograph (PET) for brain studies has been developed. It consists of five detector rings (240 BGOs/ring). New multisegment photomultiplier tubes (PMTs) were adopted for the system with 5-mm-wide BGOs. The system is designed to examine a patient sitting or lying down on a chair/bed couch. The functions of PMT auto gain control and real-time image display are implemented in the system. The physical performance of the system was evaluated: the spatial resolution is 3.5 mm in the transaxial plane and 5.7 mm in the axial direction, and the total system sensitivity is 109 kcps/ mu Ci/ml for a uniform phantom 20 cm in diameter with a pulse height threshold of 350 keV.>